1. Field of the Invention
The present invention relates to a semiconductor memory information storage apparatus which stores information, such as content data, in a semiconductor memory, and a method of controlling writing for storing information, such as content data, in a semiconductor memory.
2. Description of the Related Art
Some information storage apparatuses which store content data utilize, as their storage media, semiconductor memories which allow data to be written and read in units of blocks. This semiconductor memory has an advantage of high reliability because it includes no operating part. On the other hand, the number of times data can be written to the semiconductor memory is small as compared to the case of writing to a hard disk or the like. In particular, if only a specific block is used, the block becomes a defective area (called an “acquired backdrop”). One of conventional techniques which overcome such a kind of problem is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-144478. In a semiconductor memory information storage apparatus disclosed in this patent document, the number of times of writing is counted by block every time content data is written to a semiconductor memory. At the time of writing data, the number of times of writing of every block is read, and content data is written to unused blocks in ascending order of the number of times of writing.
However, in recent years, the capacity of a semiconductor memory has been upsizing. A method of reading the number of times of writing for all blocks every time data is written and then selecting an unused block with a small number of times of writing as disclosed in patent document 1 is no longer an efficient approach. Accordingly, there is a need for an information storage apparatus which can select an unused block in real time during operation of writing content data and can cause the number of times of writing to be uniform among all blocks.